1. Field of the Invention
The present invention relates to a musical score position estimating device, a musical score position estimating method, and a musical score position estimating robot.
2. Description of Related Art
In recent years, thanks to remarkable developments in the physical functions of robots, attempts have been made to support humans doing housework or nursing. For the purpose of coexistence of humans and robots, there is a need for natural interaction between robots and humans.
An example of a communication as an interaction between a human and a robot is a communication using music. Music plays an important role in communication between humans and, for example, persons who do not share a language can share a friendly and joyful time through the music. Accordingly, being able to interact with humans through music is essential for robots to live in harmony with humans.
As situations in which robots communicate with humans through music, for example, it can be thought that the robots could sing to accompaniments or singing voices or move their bodies to the music.
Regarding such a robot, techniques of analyzing musical score information and causing the robots to move on the basis of the analysis result are known.
As a technique of recognizing what musical note is described in a musical score, a technique of converting image data of a musical score into musical note data and automatically recognizing the musical score has been suggested (for example, JP Patent No. 3147846). As a technique of analyzing a metrical structure of tune data on the basis of musical score data and structure analysis data grouped in advance and estimating tempos from audio signals in performance, a beat tracking method has been suggested (for example, see JP-A-2006-201278).
In the technique of analyzing the metrical structure described in JP-A-2006-201278, only the structure based on the musical score is analyzed. Accordingly, when a robot tries to sing to audio signals collected by the robot and a piece of music is started from the middle part thereof, it is not clear what portion of the music is currently performed, and thus the robot fails to extract the beat time or tempo of the piece in performance. In addition, when a human performs a piece of music, the tempo of the performance may vary and thus there is a problem in that the robot may fail to extract the beat time or tempo of the piece in performance.
In the past, the metrical structure or the beat time or the tempo of the piece of music was extracted on the basis of the musical score data. Accordingly, when a piece of music is actually performed, it is not possible to detect what portion of the musical score is currently performed with high precision.